It is possible that someone messed up the date for the automatic mailing of the minutes, so that it went out exactly one day early. One person who received it said it hit his mail box at exactly 2 p.m. ET Tuesday.

The recipients of the email included staffers of the House Financial Services Committee. Some on the staff of the Senate banking committee also received it, according to a staffer.

One congressional staffer who received the minutes yesterday said he did not realize they had been released early until the news broke this morning.

The minutes were emailed yesterday afternoon to around 100 people, including some Capitol Hill staffers and trade lobbyists, according to a person familiar with the matter. When it discovered the early release this morning, the Fed decided to move up the time of its official release. It had been scheduled for 2 p.m. today.

Because the minutes were released while the market was open, it's possible that someone might have attempted to trade on those minutes. Such trading might not even violate securities laws, which generally allow outsiders to trade on inadvertently leaked non-public information.

The Securities and Exchange Commission said it had been informed of the early release today, but would not comment on whether it is investigating any trading that might have occurred in connection with the minutes.